| GigaRoc |
01-15-2008 04:02 PM |
Daemonizing in C Help
Code:
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <inotifytools/inotifytools.h>
#include <inotifytools/inotify.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <syslog.h>
#include <errno.h>
#include <pwd.h>
#include <signal.h>
#define DAEMON_NAME "gnotify"
/* Change this to the user under which to run */
#define RUN_AS_USER "gigaroc"
#define EXIT_SUCCESS 0
#define EXIT_FAILURE 1
FILE *oFile;
static void child_handler(int signum)
{
switch(signum) {
case SIGALRM: exit(EXIT_FAILURE); break;
case SIGUSR1: exit(EXIT_SUCCESS); break;
case SIGCHLD: exit(EXIT_FAILURE); break;
}
}
static void daemonize( const char *lockfile )
{
pid_t pid, sid, parent;
int lfp = -1;
/* already a daemon */
if ( getppid() == 1 ) return;
/* Create the lock file as the current user */
if ( lockfile && lockfile[0] ) {
lfp = open(lockfile,O_RDWR|O_CREAT,0640);
if ( lfp < 0 ) {
syslog( LOG_ERR, "unable to create lock file %s, code=%d (%s)",
lockfile, errno, strerror(errno) );
exit(EXIT_FAILURE);
}
}
/* Drop user if there is one, and we were run as root */
if ( getuid() == 0 || geteuid() == 0 ) {
struct passwd *pw = getpwnam(RUN_AS_USER);
if ( pw ) {
syslog( LOG_NOTICE, "setting user to " RUN_AS_USER );
setuid( pw->pw_uid );
}
}
/* Trap signals that we expect to recieve */
signal(SIGCHLD,child_handler);
signal(SIGUSR1,child_handler);
signal(SIGALRM,child_handler);
/* Fork off the parent process */
pid = fork();
if (pid < 0) {
syslog( LOG_ERR, "unable to fork daemon, code=%d (%s)",
errno, strerror(errno) );
exit(EXIT_FAILURE);
}
/* If we got a good PID, then we can exit the parent process. */
if (pid > 0) {
/* Wait for confirmation from the child via SIGTERM or SIGCHLD, or
for two seconds to elapse (SIGALRM). pause() should not return. */
alarm(2);
pause();
exit(EXIT_FAILURE);
}
/* At this point we are executing as the child process */
parent = getppid();
/* Cancel certain signals */
signal(SIGCHLD,SIG_DFL); /* A child process dies */
signal(SIGTSTP,SIG_IGN); /* Various TTY signals */
signal(SIGTTOU,SIG_IGN);
signal(SIGTTIN,SIG_IGN);
signal(SIGHUP, SIG_IGN); /* Ignore hangup signal */
signal(SIGTERM,SIG_DFL); /* Die on SIGTERM */
/* Change the file mode mask */
umask(0);
/* Create a new SID for the child process */
sid = setsid();
if (sid < 0) {
syslog( LOG_ERR, "unable to create a new session, code %d (%s)",
errno, strerror(errno) );
exit(EXIT_FAILURE);
}
/* Change the current working directory. This prevents the current
directory from being locked; hence not being able to remove it. */
if ((chdir("/")) < 0) {
syslog( LOG_ERR, "unable to change directory to %s, code %d (%s)",
"/", errno, strerror(errno) );
exit(EXIT_FAILURE);
}
/* Redirect standard files to /dev\null */
/* taken out for now
freopen( "/dev\null", "r", stdin);
freopen( "/dev\null", "w", stdout);
freopen( "/dev\null", "w", stderr);
*/
/* Tell the parent process that we are A-okay */
kill( parent, SIGUSR1 );
}
int main() {
/* Initialize the logging interface */
openlog( DAEMON_NAME, LOG_PID, LOG_LOCAL5 );
syslog( LOG_INFO, "starting" );
/* One may wish to process command line arguments here */
/* Daemonize */
daemonize( "/var/lock/subsys/" DAEMON_NAME );
/* Main program */
/* open outfile */
oFile = fopen ("/etc/gnotify/events.log", "wt");
fprintf (oFile, "File Initialized\n");
/*Set events we are watching */
int eventnum = IN_MODIFY | IN_MOVED_FROM | IN_MOVED_TO | IN_CREATE | IN_DELETE ;
/* initialize and watch the entire directory tree from the current working
directory downwards for all events */
if ( !inotifytools_initialize()
|| !inotifytools_watch_recursively( "/mnt/", eventnum ) ) {
fprintf(stderr, "%s\n", strerror( inotifytools_error() ) );
return -1;
}
/*set time format to 24 hour time, HH:MM:SS*/
inotifytools_set_printf_timefmt( "%T" );
/*Output all events as "<timestamp> <path> <events>"*/
struct inotify_event * event = inotifytools_next_event( -1 );
while ( event ) {
/*Gets time from the time.h and cuts it up for output later*/
char* gTime="";
char gDay[3]="";
char gMonth[4]="";
char gYear[5]="";
char gTime1[26];
time_t timer;
timer=time(NULL);
gTime = asctime(localtime(&timer));
strcpy(gTime1,gTime);
gMonth[0] = gTime1[4];
gMonth[1] = gTime1[5];
gMonth[2] = gTime1[6];
gDay[0] = gTime1[8];
gDay[1] = gTime1[9];
gYear[0] = gTime1[20];
gYear[1] = gTime1[21];
gYear[2] = gTime1[22];
gYear[3] = gTime1[23];
/*output handled in two steps */
fprintf(oFile,"%s %s %s ",gDay,gMonth,gYear);
inotifytools_fprintf(oFile,event, "%T %w%f %e\n" );
event = inotifytools_next_event( -1 );
/*because the file is always running we need to update the log file at all times*/
fflush( oFile );
}
printf("Program Exiting\n");
fclose(oFile);
syslog( LOG_NOTICE, "terminated" );
closelog();
return 0;
}
ok, here's the problem: the program doesn't output anything
At first i noticed that i was re-directing std output to NULL so i commented that out
And i can still output to the command prompt, but i can not out put to a file
Also the program seems to terminate after the first fprintf
i know because i had a lot of printf("here *description*\n"); that i took out
it's been a while since i have programmed so it's possible that it's a logic error on my part
Thank you for your help ^_^
Kevin |
